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| author | Daniel P. Berrangé <berrange@redhat.com> | 2024-01-31 17:02:15 +0000 |
|---|---|---|
| committer | Daniel P. Berrangé <berrange@redhat.com> | 2024-03-19 20:17:12 +0000 |
| commit | e79f8b8b2d70a85200af14deb65d399597d780f5 (patch) | |
| tree | 18b9ce7220d581023b7f1c7ba44fe394f1ea9066 | |
| parent | c62d54d0a8067ffb3d5b909276f7296d7df33fa7 (diff) | |
| download | focaccia-qemu-e79f8b8b2d70a85200af14deb65d399597d780f5.tar.gz focaccia-qemu-e79f8b8b2d70a85200af14deb65d399597d780f5.zip | |
seccomp: report EPERM instead of killing process for spawn set
When something tries to run one of the spawn syscalls (eg clone), our seccomp deny filter is set to cause a fatal trap which kills the process. This is found to be unhelpful when QEMU has loaded the nvidia GL library. This tries to spawn a process to modprobe the nvidia kmod. This is a dubious thing to do, but at the same time, the code will gracefully continue if this fails. Our seccomp filter rightly blocks the spawning, but prevent the graceful continue. Switching to reporting EPERM will make QEMU behave more gracefully without impacting the level of protect we have. https://gitlab.com/qemu-project/qemu/-/issues/2116 Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
| -rw-r--r-- | system/qemu-seccomp.c | 10 |
1 files changed, 5 insertions, 5 deletions
diff --git a/system/qemu-seccomp.c b/system/qemu-seccomp.c index 4d7439e7f7..98ffce075c 100644 --- a/system/qemu-seccomp.c +++ b/system/qemu-seccomp.c @@ -74,7 +74,7 @@ const struct scmp_arg_cmp sched_setscheduler_arg[] = { #define RULE_CLONE_FLAG(flag) \ { SCMP_SYS(clone), QEMU_SECCOMP_SET_SPAWN, \ - ARRAY_SIZE(clone_arg ## flag), clone_arg ## flag, SCMP_ACT_TRAP } + ARRAY_SIZE(clone_arg ## flag), clone_arg ## flag, SCMP_ACT_ERRNO(EPERM) } /* If no CLONE_* flags are set, except CSIGNAL, deny */ const struct scmp_arg_cmp clone_arg_none[] = { @@ -214,13 +214,13 @@ static const struct QemuSeccompSyscall denylist[] = { 0, NULL, SCMP_ACT_TRAP }, /* spawn */ { SCMP_SYS(fork), QEMU_SECCOMP_SET_SPAWN, - 0, NULL, SCMP_ACT_TRAP }, + 0, NULL, SCMP_ACT_ERRNO(EPERM) }, { SCMP_SYS(vfork), QEMU_SECCOMP_SET_SPAWN, - 0, NULL, SCMP_ACT_TRAP }, + 0, NULL, SCMP_ACT_ERRNO(EPERM) }, { SCMP_SYS(execve), QEMU_SECCOMP_SET_SPAWN, - 0, NULL, SCMP_ACT_TRAP }, + 0, NULL, SCMP_ACT_ERRNO(EPERM) }, { SCMP_SYS(clone), QEMU_SECCOMP_SET_SPAWN, - ARRAY_SIZE(clone_arg_none), clone_arg_none, SCMP_ACT_TRAP }, + ARRAY_SIZE(clone_arg_none), clone_arg_none, SCMP_ACT_ERRNO(EPERM) }, RULE_CLONE_FLAG(CLONE_VM), RULE_CLONE_FLAG(CLONE_FS), RULE_CLONE_FLAG(CLONE_FILES), |